Charter Communications Inc. Chief Executive Tom Rutledge said he has been "surprised" by the number of customers opting to take Internet broadband service only, which amounts to more evidence of online video gaining on traditional TV.

Mr. Rutledge hinted at that issue in his comments, made on an analyst conference call for Charter's third-quarter results, when he attributed the growth in "broadband-only customers" in part to changing consumer tastes. He said, however, that the trend was largely due to...